US3696399A - Range expansion method and apparatus for multichannel pulse analysis - Google Patents

Range expansion method and apparatus for multichannel pulse analysis Download PDF

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Publication number
US3696399A
US3696399A US71441A US3696399DA US3696399A US 3696399 A US3696399 A US 3696399A US 71441 A US71441 A US 71441A US 3696399D A US3696399D A US 3696399DA US 3696399 A US3696399 A US 3696399A
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data
channels
pulses
voltage
converter
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US71441A
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Robert T Klein
Robert L Kreiselman
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Coulter Electronics Inc
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Coulter Electronics Inc
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N15/00—Investigating characteristics of particles; Investigating permeability, pore-volume or surface-area of porous materials
    • G01N15/10—Investigating individual particles
    • G01N15/1031—Investigating individual particles by measuring electrical or magnetic effects
    • G01N15/12—Investigating individual particles by measuring electrical or magnetic effects by observing changes in resistance or impedance across apertures when traversed by individual particles, e.g. by using the Coulter principle
    • G01N15/131—Details
    • G01N15/132—Circuits

Definitions

  • Multichannel pulse analyzers are in increasing use in almost all fields where comparative, high speed, data collection and analysis can be useful. Theoretically, the more channels the data can be separated into, the greater the accuracy or resolution which can be obtained. Practically, cost, size, complexity, maintainence, etc. all increase as the number of channels increase; hence, a compromise often must be made. Often, the compromise results in the purchase of an analyzer having too few channels.
  • a multichannel analyzer Once a multichannel analyzer is built, it is not easily converted to increase the number of channels; however, devices have been designed to increase the usefulness of a fixed channel system. Such devices are often called range expanders, since they take the data in a selected one or ones of the channels and spread or expand this data by amplifying means, to give the effect that the data was collected in numerous adjacent channels. For example, if an analyzer contained 100 channels and it is desired to examine in detail the data in the l() channels numbered 50 to 60, the stored data in those memory channels could be amplified and the selected ten channels thereby spread or expanded by the selected amplification factor.
  • the invention provides method and apparatus for an "expand then store multichannel operation, whereby data gathering has increased the efficient use of the limited number of data channels.
  • the desired range of channels is selected by offset means and a corresponding width amplifying function or expansion factor is applied to each pulse.
  • a to D conversion and memory storage concerns only the range of desired data, which has been expanded to fill the entire multichannel memory.
  • One particular use for this invention is in the field of particle analysis, in which the source of data pulses are generated by a particle analyzer, such as a Coulter Counter.
  • FIG. 1 is a schematic illustrating the broad concepts of the invention
  • FIG. 2 shows three graphs A, B and C of collected data, in which graphs B and C are progressive range expansions of graph A;
  • FIG. 3 shows a more detailed schematic of the inventron.
  • FIG. I there is shown an expand then store" arrangement for a typical multichannel memory unit 10.
  • the memory possesses 100 channels and receives data in digital form from an A to D con- O particulate system, in which the amplitude of each pulse of the train represents the size of a particle.
  • a particle analyzing pulse source 14 of this type is a Coulter Counter.”
  • an attenuator 16 is provided.
  • the attenuator is fixed" in that once it is set, it treats all input pulses with the same amplification or attenuation factor.
  • the fixed factor can be adjusted whenever the pulse source 14 is changed so that the range expansion can be normalized. For example, a Coulter Counter Model A particle analyzer would require a different attenuation factor from a Coulter Counter" Model B type of particle analyzer.
  • the output from the attenuator I6 is connected to a clamp 18, which has the purpose of restoring a true ground reference or base level. At this point the data signals are ready for the expansion process.
  • the determination of how much expansion and which channels of data are to be retained and expanded is typically an operator controlled function.
  • the source of pulses and the nature of the data being collected often establish prerequisites which aid the human operator to preset the range expansion parameters. Thereafter, an examination of the data, as it is being collected, may indicate the channel range requiring expansion. In some circumstances, the channel range of most interest might not be known until after the data has been collected. In the latter case, a recycle of the data collection process would be accomplished after the expansion parameters were set.
  • FIG. 2A shows a chart of a typical distribution of particle size in a particulate system.
  • Each of the 100 channels represents a particle size, with the size increasing channel by channel, and the number of particles in each size channel being designated cumulatively by the Y axis position or height at the channel position.
  • the pulse source 14 is a Coulter Counter" analyzer
  • the data in lower channels would be recognized as being greatly influenced by electronic noise, to the extent that it is merely a measure of noise pulses and not particle size. For that reason, channels one through 24 could be excluded from consideration. Because of coincidence of particles in the scanning ambit of a Coulter Counter analyzer and random very large particles of little interest, the data in channels above is usually considered insignificant. Hence, of the original channels, only 50 of them-those between 25 and 75- would be expected to carry data of interest.
  • each of the I00 channels is to store data originating from pulse amplitudes in 1 volt increments, i.e., channel one stores the number of pulses having amplitudes lying between 0 and 1 volt; channel 50 responds to pulses having amplitudes lying between 49 and 50 volts; and channel 100 correlates to particle pulses in the 99 to 100 volt size.
  • the A to D converter 12 has a full scale capability of 100 volts. Accordingly, use of only channels 25 to 75 is use of only one-half of the voltage capability or range of the system, more particularly the input range of the A to D converter 12 and thus the memory 10.
  • an expansion factor of 2 the reciprocal of one-half, is available to maximize the use of the system.
  • an expansion factor of 4 would be available, so as to spread the width of the 25 channels of data over the entire one hundred channels receivable by the A to D converter 12 and retainable in the memory 10.
  • an amplifier 20, having an operator-settable width control 22 is provided at the output of the clamp 18.
  • a simple potentiometer would be sufficient for setting the width of the channel range employed to be equal to the full scale range of the system.
  • the dial (not shown), by which the operator sets the width control 22, could be marked to show the fractional values of the channels being employed, compared to full scale, i.e., one-half and one-fourth in the above two examples, or their reciprocal, expansion factors 2 and 4, or the total number of channels being employed, 50 and 25. The latter would seem to be the most convenient for the operator.
  • the setting of the width control 22 of the amplifier 20 causes the pulses from the clamp 18 to be amplified by the above defined expansion factor, and the thus amplified pulses then are applied to the input of the A to D converter 12.
  • the amplifier 20 can be of the operational type, having resistive feedback to determine its gain.
  • the output from the amplifier 20 for pulses destined for channel 25 would be 50 volts and for channel 75 would be 150 volts.
  • the latter is in excess of full scale and must be corrected.
  • a system offset control 24 which is coupled to the A to D converter, and operates to subtract, from the instantaneous voltage of the signal pulses from the amplifier 20, a value sufficient to cause the expansion-factor amplified signal pulse for the lowest channel, in this example 50 volts and channel 25, to equal zero volts and thus fall into the lowest channel of the memory 10.
  • the system offset control 24 would subtract 50 volts from all signals being fed to the converter 12, and thereby cause the I50 volt signals originally designated for channel 75 to become 100 volt signals for receipt by channel one hundred; hence, full scale utilization of the system.
  • the zero offset control includes a potentiometer 26 having as one terminal end the slider of another potentiometer 28, the latter being coupled between +V and V.
  • the other tenninal ,of the potentiometer 26 is coupled to a source of reference voltage V, and its slider is connected to the A to D converter 12.
  • a slider 30 is tapped to the potentiometer 26 for preset control purposes next discussed.
  • the potentiometers 28 and 30 are preset controls, with the setting of the slider of the potentiometer 28 employed to set the zero channel to match with a system zero setting, and the potentiometer 30 is to set the upper scale end of the system; hence these two controls are for tracking purposes and, once set for the system, should need little if any changing, and are not a dynamic part of the range expansion circuitry. If the pulse source 14 was a Coulter Counter" analyzer having threshold controls, it would be set to zero threshold and then the potentiometer 28 adjusted to provide a zeroed response. Likewise, the slider 30 would be set so that known size pulses in the high range, such as for channel 90, are collected in the proper channel; i.e., 90.
  • a further preset control is provided by a potentiometer 32, which is interposed between the amplifier 20 and the A to D converter 12, and provides a full scale trim adjustment.
  • the full scale output from the amplifier 20 should be slightly greater than the full scale range of the A to D converter 12; thus, all one hundred channels are certain of being utilized.
  • the width control 22 would be set for channels and thus be applying a unity or no expansion factor, and the offset control would be set at zero so as to provide no offset.
  • the width control 22 would be set to fifty channels and thereby apply an expansion factor of two to the A to D converter. While at the same time, the offset control 24 would be set so that channel 25 was the lowest channel of interest and thus 50 volts of offset is provided by way of the potentiometer 26 to the A to D converter 12. An examination of FIG. 2B will reveal an irregularity in the plotted graph between channels 50 and 55.
  • the above discussed voltages are only being selected for use of whole numbers. It is likely that full scale in a commercial embodiment would be closer to 10 volts and not 100 volts. Likewise, and not mentioned above, the memory output would be received by one or more recording devices, illustrated in FIG. 1 by a readout block 34.
  • FIG. 3 there is shown a form of the range expansion apparatus which can operate in many commercial environments. Elements common to those in FIG. I carry the same reference numerals. For simplicity, FIG. 3 does not show the pulse source 14, the attenuator 16, the memory 10, the A to D converter 12, or the readout 34, but provides input and output to some of these elements.
  • the output from the attenuator 16 is carried by a lead 36 to a dc. filtering capacitor 38 and then to the clamp 18.
  • the output from the clamp goes to a normally closed, disconnect switch 40 and also to one side of a comparator 42.
  • the other side of the comparator is connected to the output from a buffer amplifier 44, which acts to linearize the offset adjustment potentiometer 26 to which it is coupled.
  • the output from the buffer amplifier 44 also is coupled, by way of a lead 46, to a peak detector and hold circuit 48, which is a significant circuitry addition in FIG. 3.
  • a majority of the other elements added in FIG. 3 beyond that of FIG. 1 are in support of the peak detector and hold circuit as well as provide control to and from the A to D converter.
  • Such circuit 48 per se is well known, often is called a sample and hold or a pulse stretcher, and operates to provide output pulses shaped for easier and more reliable processing by subsequent stages, such as the A to D converter 12, to which an output lead 50 from the amplifier is coupled, by way of the width control 22 and the amplifier 20.
  • the comparator output on lead 52 also is coupled by a lead 62 to a reset input of the A to D converter.
  • the latter connection arrangement is a safety feature, since the A to D converter 12 is internally constructed to be self-resetting after each data pulse.
  • the converter also provides a hold control signal, which is applied to a lead 64 through the OR gate 54. In this manner, if the converter operates slower than the train of data pulses otherwise would dictate, the converter can force the sample and hold circuit 48 to hold the in process pulse until the converter has finished converting it.
  • any data pulse is received by the clamp 18, independent of whether or not that pulse is to be expanded, it normally will pass through the disconnect switch 40 and be received by the peak detecting portion of the circuit 48; however, in the absence of an output signal from the comparator, which signifies that the data pulse is large enough to be expanded and stored, there is no input from the lead 56 to the hold circuit portion of the circuit 48. As a consequence, the too small data pulse is not held or stretched. Moreover, there is not generated in the hold circuit portion of the circuit 48 an A to D start signal on a lead 66, which is coupled both to a start input of the A to D converter 12 as well as the set input 8 of the bistable device. Accordingly, the too small data pulses, although they pass through the peak detector and hold circuit 48, and are fed to the width control 22 and the amplifier 20, they are not stretched and are not received by the A to D converter.
  • Data pulses which are large enough to activate the comparator 42 do, by way of the OR 54 and the hold enabling input 56, trigger the hold circuit portion and, by way of the start lead 66, start the A to D converter and set the bistable device 60. As a result, these data pulses are stretched and received by the A to D converter.
  • the setting of the bistable device 60 open-circuits the disconnect switch 40, by way of a coupling lead 68, to prevent the next following data pulse from being applied to the peak detector portion of the circuit 48 until after the reset operation, above discussed.
  • a method according to claim 1 further comprising establishing electronically, by said determining, the
  • a method in which the data, prior to storage, is in the form of signal pulses of varying amplitude and said applying of the expansion factor amplifies, proportional to the expansion factor, at least the signal pulses to be received in the specific range of channels of interest. 5. A method according to claim 4 in which voltage offsetting defines the highest channel of the specific range and causes the expansion factor amplified signal pulses acceptable by the highest channel of the specific range to have the same maximum amplitude as that acceptable by the highest channel of the originally available channels. 6. A method according to claim 4 in which voltage offsetting defines the lowest channel of the specific range and causes the expansion factor amplified signal pulses acceptable by the lowest channel of the specific range to have the same minimum amplitude as that acceptable by the lowest channel of the originally available channels.
  • a method according to claim 6 further comprising processing all signal pulses exceeding said minimum amplitude by peak detecting and stretching,
  • a method according to claim 8 wherein said defining is accomplished by voltage offsetting.
  • a method according to claim 10 wherein said voltage offsetting causes the lowest channel of the specific range to have its low end scaled to equal the low end of the lowest channel of the originally available channels.
  • a method according to claim 10 wherein said voltage offsetting causes the highest channel of the specific range to have its high end scaled to equal the high end of the highest channel of the originally available channels.
  • a method according to claim 1 which further comprises generating the data in the form of a train of pulses of varying amplitude, the pulse amplitudes defining the original channels of destination, and amplifying the pulses by said applying of the expansion factor, whereby the pulses destined for the specific range of channels become amplified to encompass the full scale of the originally available channels.
  • each of the herein defined apparatus means being operatively coupled to one another so that, prior to the memory storage of data, the data is range expanded so as to be capable of being stored in the total number of available channels.
  • Apparatus according to claim 18 in which said means for determing the number of channels of interest is constructed and arranged, with respect to said means for applying the expansion factor, to establish a mathematic value for the expansion factor.
  • Apparatus according to claim 19 in which said means for applying the expansion factor is an amplifier which is to receive the data pulses prior to the data storage, and
  • said means for determining the number of channels of interest is an amplification control coupled to said amplifier and sealed with reference to the total number of available channels.
  • Apparatus according to claim 20 in which said amplifier and said amplification control are constructed and scaled such that the mathematic product of the selected number of channels of interest and the established expansion factor equals the total number of available channels.
  • Apparatus according to claim 20 in which an A to D converter is provided and is coupled to be responsive said amplifier and to said means for selecting the specific range of channels of interest.
  • Apparatus according to claim 22 in which said specific range selecting means comprises data pulse amplitude offsetting means for changing the instantaneous amplitude of each data pulse.
  • said amplitude offsetting means comprises a voltage subtracting arrangement which, when set to a specific range of channels, subtracts from each data pulse a voltage equal to the mathematic product of the low end voltage level of the lowest channel of the selected range and the expansion factor.
  • amplitude offsetting means comprises a voltage subtracting arrangement which, when set to a specific range of channels, subtracts from each data pulse a voltage equal to the low end voltage of the lowest channel of the selected range.
  • control and comparison circuitry are provided and coupled to an input of said A to D converter and operate to enable said converter to receive only those data pulses having amplitudes greater than that subtracted by said voltage offsetting means.
  • Apparatus according to claim 28 in which said amplitude offsetting means comprises a voltage subtracting arrangement which, when set to a specific range of channels, subtracts from each data pulse a voltage equal to the low end voltage of the lowest channel of the selected range.
  • Apparatus according to claim 29 in which an A to D converter is provided with one input coupled to receive data pulses to which has been applied the expansion factor.
  • control and comparison circuitry are provided and coupled to an input of said A to D converter and operate to enable said converter to receive only those data pulses having amplitudes greater than that subtracted by said voltage offsetting means.
  • both said potentiometer arrangements are coupled to an A to D converter and said potentiometer arrangements operate with respect to the data pulses to establish a low threshold scaled to the lowest channel of the selected range and to establish the expansion factor such that the amplitude of data pulses for the highest channel of the selected range is substantially equal to full scale of said A to D converter.
  • Apparatus according to claim 34 in which a data pulse source is provided in the form of a particle analyzer.

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Cited By (14)

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Publication number Priority date Publication date Assignee Title
US3981006A (en) * 1973-07-06 1976-09-14 Sony Corporation Signal transmitting apparatus using A/D converter and monostable control circuit
US3981005A (en) * 1973-06-21 1976-09-14 Sony Corporation Transmitting apparatus using A/D converter and analog signal compression and expansion
US5089820A (en) * 1989-05-22 1992-02-18 Seikosha Co., Ltd. Recording and reproducing methods and recording and reproducing apparatus
US5184062A (en) * 1990-05-11 1993-02-02 Nicolet Instrument Corporation Dynamically calibrated trigger for oscilloscopes
US5442492A (en) * 1993-06-29 1995-08-15 International Business Machines Corporation Data recovery procedure using DC offset and gain control for timing loop compensation for partial-response data detection
US20110121191A1 (en) * 2009-11-26 2011-05-26 Steffen Kappler Circuit arrangement for counting x-ray radiation x-ray quanta by way of quanta-counting detectors, and also an application-specific integrated circuit and an emitter-detector system
US20140268141A1 (en) * 2013-03-15 2014-09-18 Particles Plus, Inc. Pulse scope for particle counter
CN110568468A (zh) * 2019-08-27 2019-12-13 福州智元仪器设备有限公司 一种辐射脉冲计数突变算法
US10718703B2 (en) 2014-04-30 2020-07-21 Particles Plus, Inc. Particle counter with advanced features
US10983040B2 (en) 2013-03-15 2021-04-20 Particles Plus, Inc. Particle counter with integrated bootloader
US11169077B2 (en) 2013-03-15 2021-11-09 Particles Plus, Inc. Personal air quality monitoring system
US11579072B2 (en) 2013-03-15 2023-02-14 Particles Plus, Inc. Personal air quality monitoring system
US11988591B2 (en) 2020-07-01 2024-05-21 Particles Plus, Inc. Modular optical particle counter sensor and apparatus
US12044611B2 (en) 2013-03-15 2024-07-23 Particles Plus, Inc. Particle counter with integrated bootloader

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DE3744398A1 (de) * 1987-12-29 1989-07-13 Asea Brown Boveri Verfahren und vorrichtung zur registrierung von signalkurven

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US3359410A (en) * 1964-04-23 1967-12-19 Infotronics Corp Automatic base line drift corrector circuit
US3421083A (en) * 1965-03-19 1969-01-07 Abbey Electronics Corp Digital indicating device for dc voltage source
US3475748A (en) * 1965-08-09 1969-10-28 Robert J Price Gain stabilization device
US3491295A (en) * 1966-11-21 1970-01-20 Fluke Mfg Co John R.m.s. instrument having voltage controlled oscillator in feed-back loop
US3500247A (en) * 1968-01-08 1970-03-10 Communications Satellite Corp Non-linear pulse code modulation with threshold selected sampling

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Publication number Priority date Publication date Assignee Title
US3292150A (en) * 1963-04-23 1966-12-13 Kenneth E Wood Maximum voltage selector
US3348216A (en) * 1963-12-09 1967-10-17 Billy H Vinson Method and circuits for storing electrical energy
US3359410A (en) * 1964-04-23 1967-12-19 Infotronics Corp Automatic base line drift corrector circuit
US3421083A (en) * 1965-03-19 1969-01-07 Abbey Electronics Corp Digital indicating device for dc voltage source
US3475748A (en) * 1965-08-09 1969-10-28 Robert J Price Gain stabilization device
US3491295A (en) * 1966-11-21 1970-01-20 Fluke Mfg Co John R.m.s. instrument having voltage controlled oscillator in feed-back loop
US3500247A (en) * 1968-01-08 1970-03-10 Communications Satellite Corp Non-linear pulse code modulation with threshold selected sampling

Cited By (28)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3981005A (en) * 1973-06-21 1976-09-14 Sony Corporation Transmitting apparatus using A/D converter and analog signal compression and expansion
US3981006A (en) * 1973-07-06 1976-09-14 Sony Corporation Signal transmitting apparatus using A/D converter and monostable control circuit
US5089820A (en) * 1989-05-22 1992-02-18 Seikosha Co., Ltd. Recording and reproducing methods and recording and reproducing apparatus
US5184062A (en) * 1990-05-11 1993-02-02 Nicolet Instrument Corporation Dynamically calibrated trigger for oscilloscopes
US5442492A (en) * 1993-06-29 1995-08-15 International Business Machines Corporation Data recovery procedure using DC offset and gain control for timing loop compensation for partial-response data detection
US20110121191A1 (en) * 2009-11-26 2011-05-26 Steffen Kappler Circuit arrangement for counting x-ray radiation x-ray quanta by way of quanta-counting detectors, and also an application-specific integrated circuit and an emitter-detector system
CN102135626A (zh) * 2009-11-26 2011-07-27 西门子公司 计数x射线量子的电路装置以及特定用途集成电路和系统
US8450695B2 (en) 2009-11-26 2013-05-28 Siemens Aktiengesellschaft Circuit arrangement for counting X-ray radiation X-ray quanta by way of quanta-counting detectors, and also an application-specific integrated circuit and an emitter-detector system
CN102135626B (zh) * 2009-11-26 2014-06-04 西门子公司 计数x射线量子的电路装置以及特定用途集成电路和系统
US11169077B2 (en) 2013-03-15 2021-11-09 Particles Plus, Inc. Personal air quality monitoring system
US9140639B2 (en) * 2013-03-15 2015-09-22 Particles Plus, Inc. Pulse scope for particle counter
US12405205B2 (en) 2013-03-15 2025-09-02 Particles Plus, Inc. Personal air quality monitoring system
US12044611B2 (en) 2013-03-15 2024-07-23 Particles Plus, Inc. Particle counter with integrated bootloader
US10983040B2 (en) 2013-03-15 2021-04-20 Particles Plus, Inc. Particle counter with integrated bootloader
US20140268141A1 (en) * 2013-03-15 2014-09-18 Particles Plus, Inc. Pulse scope for particle counter
US11519842B2 (en) 2013-03-15 2022-12-06 Particles Plus, Inc. Multiple particle sensors in a particle counter
US11913869B2 (en) 2013-03-15 2024-02-27 Particles Plus, Inc. Personal air quality monitoring system
US11579072B2 (en) 2013-03-15 2023-02-14 Particles Plus, Inc. Personal air quality monitoring system
US11835443B2 (en) 2014-04-30 2023-12-05 Particles Plus, Inc. Real time monitoring of particle count data
US11841313B2 (en) 2014-04-30 2023-12-12 Particles Plus, Inc. Power management for optical particle counters
US11846581B2 (en) 2014-04-30 2023-12-19 Particles Plus, Inc. Instrument networking for optical particle counters
US10718703B2 (en) 2014-04-30 2020-07-21 Particles Plus, Inc. Particle counter with advanced features
US12306088B2 (en) 2014-04-30 2025-05-20 Particles Plus, Inc. Particle counter with advanced features
CN110568468B (zh) * 2019-08-27 2023-01-10 福州智元仪器设备有限公司 一种辐射脉冲计数突变算法
CN110568468A (zh) * 2019-08-27 2019-12-13 福州智元仪器设备有限公司 一种辐射脉冲计数突变算法
US11988591B2 (en) 2020-07-01 2024-05-21 Particles Plus, Inc. Modular optical particle counter sensor and apparatus
US12055474B2 (en) 2020-07-01 2024-08-06 Particles Plus, Inc. Modular optical particle counter sensor and apparatus
US12436084B2 (en) 2020-07-01 2025-10-07 Particles Plus, Inc. Modular optical particle counter sensor and apparatus

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FR2107467A5 (enExample) 1972-05-05
GB1353953A (en) 1974-05-22
DE2103816B2 (de) 1977-09-22

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